X-ray receivers known from the prior art encounter the problem that, particularly in the case of mobile x-ray apparatuses used in traumatology, the x-ray receiver, for example an x-ray cassette with a film-foil combination or an x-ray cassette with a so-called storage foil, must be placed in the region of a patient in order to detect the patient or a part of the patient in a projection by way of x-rays. When detecting a patient by way of a previously described arrangement, the problem often arises that the correct irradiation period and/or irradiation intensity for the irradiation of a storage medium detecting the x-rays is left up to the experience of the operating personnel. This has the consequence that x-ray pictures are often poorly exposed and, as a following consequence, the patient is exposed to an increased radiation burden by repeated recordings—until a correct irradiation of the storage medium.